A BACTERIUM CAUSING A DISEASE OF SUGAR-BEET 
AND NASTURTIUM LEAVES 
By NELLIE A. Brown, Assistant Pathologist, Laboratory of Plant Pathology, and 
Clara O. Jamieson, Scientific Assistant, Office of Cotton and Truck Disease and 
Sugar-Plant Investigations, Bureau of Plant Industry 
INTRODUCTION 
The bacterial disease described in this paper was first observed in the 
spring and summer of 1908 on nasturtium leaves growing near Richmond, 
Va., and on sugar-beet leaves collected from the Government plat at 
Garland, Utah. The disease on both hosts was of the leaf-spot type, but 
since the general appearance was not at all similar there was no thought 
at the time of a possible relationship between the causal organisms. 1 
Investigations of the disease as it occurred on each host were at once 
begun, but not until the studies had progressed for nearly two years did 
it become evident that there was a striking similarity in regard to both 
cultural and morphological characteristics of the bacteria isolated from 
the two kinds of diseased leaves. 
A comparative study of the bacteria followed, care being taken to use 
the same media placed under similar conditions. As a result of studies 
extending over four years, it has been found that in essential character¬ 
istics the bacterial organisms are so nearly identical that in the opinion 
of the writers the causal organism is one and the same bacterium. Any 
minor differences which occur may be attributed to individual adapta¬ 
tion due to host influence. 
OCCURRENCE AND GENERAL APPEARANCE OF THE DISEASE ON THE 
TWO HOSTS 
The material furnishing the basis of this study was received during 
the spring and summer of 1908. The diseased nasturtium leaves were 
sent in from Richmond, Va., to Dr. C. O. Townsend, then Pathologist in 
Charge of Sugar-Beet Investigations in the Bureau of Plant Industry. 
The diseased leaves had been gathered from young nasturtium plants 
growing in an open garden bed and when received were somewhat wilted 
and discolored, showing water-soaked and brownish-colored spots from 
2 to 5 mm. in diameter. Upon microscopic examination the tissue 
within and surrounding these diseased spots was seen to be filled with 
great numbers of active bacteria. 3 
1 Brown, Nellie A. A new bacterial disease of the sugar-beet leaf. Science, n. s., v. 29, no. 753, p. 915, 
1909. Jamieson, Clara O. A new bacterial disease of nasturtium. Science, n. s., v. 29, no. 753, pp. 915- 
916, 1909. 
* [Halsted, B. D.] Nasturtium blight. New Jersey Agr. Expt. Sta., 17th Ann. Rpt., [1895] 1896, p. 410, 
fig. 56,1897. 
Journal of Agricultural Research, 
Dept, of Agriculture, Washington, D. C. 
Vol. I, No. 3 
Dec. ro, 1913 
G -5 
